The present invention relates generally to accumulator apparatuses and methods for accumulating sheet articles. More particularly, the present invention relates to an improved non-marking accumulator apparatus and method for reducing or eliminating mis-registration of sheet articles processed therethrough so that accumulated sheets are fed properly.
Various accumulator apparatuses and methods have been employed in the past for accumulating sheet material or articles such as paper sheets, documents, and the like into stacks for subsequent advancement. Such accumulator apparatuses and methods have particular use in high-speed mail processing where preparation and processing of mailable articles often requires a plurality of sheet articles to be assembled into a packet for further handling which can include, for example, folding, inserting, collating, etc.
As just one example of such an accumulator apparatus, U.S. Pat. No. 5,244,200 to Manzke, commonly assigned herewith, discloses a retractable-ramp accumulator and method comprising driven endless elastic belts that feed sheets therebetween along a sheet-feeding path. A series of operatively connected and selectively retractable ramps are utilized for selectively deflecting sheets out of the sheet-feeding path for accumulating the sheets in a stack after they pass the ramps in a stacking location between the ramps and selectively releasable stop gates.
Another example of an accumulator apparatus and method is found is U.S. Pat. No. 5,775,689 to Moser et al, commonly assigned herewith.
As illustrated in the two exemplary patents identified above, it is common for prior art accumulators and methods to employ endless upper belts and lower belts for seriatim feeding of sheet articles therebetween. Both of these patents outline the basic operational, structural, and control features common to this type of machinery and well known to those skilled in the art.
A problem that exists with such prior art accumulator apparatuses and methods, however, is shown in somewhat exaggerated fashion in FIG. 1 herein. When more than two sheets S are stacked in the accumulator and the accumulator drive begins to feed the paper out of the accumulator in feed direction F, some sheets may and typically tend to shingle back and trail the accumulated set. This results in the accumulated set of sheets not being registered or xe2x80x9csquaredxe2x80x9d as shown in FIGS. 3A and 3B. When the mis-registered set is sent to downstream machinery for further processing, this could result in, for example, bad folds and, even worse, machine jamming, machine stopping, and damaged paper.
In light of the prior art accumulator apparatuses and methods as described above and their deficiencies, there remains much room for improvement in the art for an accumulator apparatus and method which reduces or eliminates mis-registration of sheet articles processed therethrough so that the accumulated sheets are fed properly and are properly xe2x80x9csquaredxe2x80x9d as shown in FIGS. 2A and 2B.
It is an object of the present invention to provide an accumulator apparatus that reduces mis-registration of sheet articles processed therethrough.
It is another object of the present invention to provide an accumulator apparatus that by reducing mis-registration of sheet articles processed therethrough, also reduces bad folds, machine jamming, machine stopping, and damaged paper.
It is a further object of the present invention to provide an accumulator method that reduces mis-registration of sheet articles as it is carried out.
It is a still further object of the present invention to provide an accumulator method that by reducing mis-registration of sheet articles as it is carried out, also reduces bad folds, machine jamming, machine stopping, and damaged paper.
Some of the objects of the invention having been stated, other objects will become evident as the description proceeds, when taken in connection with the accompanying drawings described below.